Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. U.S. Route 166 is an 166-mile (267 km) eastâ€“west United States highway. This route and US 266 are the only two remaining children of historic U.S. Highway 66, since US 666 was decommissioned in 2003. US-166 meets the old route of US-66, now designated Alt US-69, in Baxter Springs in the southeast corner of Kansas. As of 2006, the highway''s western terminus is in South Haven, Kansas at an intersection with US-81, approximately 1-mile (1.6 km) north of the northern terminus of U.S. Highway 177. From this point, it heads east for about four miles (6 km), where it intersects the Kansas Turnpike (Interstate 35) at exit 4. It then enters Arkansas City, where it meets US-77 and overlaps it for approximately two miles, splitting off near Parkerfield.